A slang phrase for the act of having sexual intercourse. The phrase is mostly used by teens talking openly to each other about having sex while disguising the true meaning of the phrase from their parents or other eavesdroppers.

Do you remember that guy I dated last year? We totally went window shopping together. It was great.

when you stand next to a window at school with ur mate, where a lot of people going in for next lesson, then you and ur mate pick out girls u would like to fuck

person 1: hey check out the girl with the nice arse
person 2: which one
person 1: the on with the black hair nearest to us
person 2: sweet!! i luv this window shopping its awesome
person 1: gud in it u see all the massive tits from here, its best when there running!!